1. Field of the Invention
The present invention relates to a semiconductor substrate, and a method for manufacturing a semiconductor substrate, a semiconductor device, and an electronic device.
2. Description of the Related Art
In recent years, an integrated circuit that uses an SOI (silicon on insulator) substrate replacing a silicon wafer formed by cutting an ingot of a single crystal semiconductor into thin slice, has been developed. An SOI substrate has a structure in which a thin single crystal silicon layer is provided on an insulating surface. By using this structure, a parasitic capacitance between a drain of a transistor and a substrate can be reduced and performance of a semiconductor integrated circuit can be improved.
There are various methods for manufacturing an SOI substrate; however, a Smart Cut (registered trademark) method is known for achieving both high quality and a high productivity (throughput) of a single crystal semiconductor layer to be formed. In the Smart Cut method, after introducing hydrogen ions into a single crystal silicon substrate (a bond wafer), the single crystal silicon substrate is bonded with another substrate (a base wafer) at a room temperature. Bonding is performed by forming strong joining by van der Waals force. After the bonding, the single crystal silicon substrate is separated with heat treatment at a temperature of about 500° C., in a region in which the hydrogen ions are introduced.
As a technical example of forming the single crystal silicon thin film using such a Smart Cut method, the one proposed by the present applicant can be noted (for example, see patent document 1; Published Patent Application Ser. No. 11-163,363).
In the patent document 1, by forming an insulating film on a glass substrate, contamination of a single crystal silicon layer is prevented, and a high-performance semiconductor device is provided.